In this research, it succeeded in the improvement of electric conductivity of yttoria stabilized zirconia (YSZ) by using the vibration caused by a piezoelectric device to develop the oxygen ion sensor which worked at the low temperature.1. YSZ thin film was prepared by the MOCVD method used Zr(DPM)_4 and Y(DPM)_3 as sauces. The YSZ film had the ionic conduction because the semicircle and the spike had been admitted on the low frequency and the high frequency respectively in the complex impedance measurement.2. Read zirconate titanate (PZT) films which was the piezoelectric material were prepared by RF-sputtering method, and the relationship between experimental conditions, structure, and morphology and the ferroelectric characteristic of the films were investigated.3. Barium titanate (BTO : BaTiO_3) films were prepared by MOCVD using Ba(DPM)_2 and Ti(O-i-C_3H_7)_2(DPM)_2 as sauces. The ionic-conduction/piezoelectric multi-functional film composed of the YSZ/BTO/Pt/MgO film was fabricated. The morphology of BTO was compact, and of YSZ was a columnar-shaped structure.4. The YSZ/piezoelectric multi-functional film was fabricated, and the effect of the piezoelectric vibration on the electric characteristic of the YSZ film were investigated.(1) The impedance of the YSZ thin film was decreased with increasing amplitude of the piezoelectric vibration.(2) Conductivity of the YSZ thin film vibrated by the piezoelectric vibration (frequency 115kHz, 40V in the voltage) conductivity is about 2×10^<-6>Ω^<-1>m^<-1>.at 90℃. The value of this conductivity was about one digit or more higher than that of the no vibration YSZ thin film. It was suggested to be able to increase conductivity of the YSZ thin film by the piezoelectric vibration.The reason that conductiveity of YSZ increases by the piezoelectric vibration is researching now.